The 2013 Atlantic Sun men's basketball tournament took place from March 6–9, 2013 at Hawkins Arena in Macon, Georgia.

The A-Sun Championship was a four-day single-elimination tournament.

The top eight teams (with the exception of Northern Kentucky) competed in the championship.

As part of their transition to Division I from Division II, Northern Kentucky was not eligible for post season play until 2017, including the A-Sun tournament.

Defending champion Belmont was not in the tournament, as they moved to the Ohio Valley Conference for the 2012-13 season.